When a user is authenticated (either via biometrics, password or other modality) the authentication is valid only on the authenticated device and the authentication is usually invalid after certain period of inactivity. It is a challenge to make the authentication persist for a longer duration without compromising security. Further, making the authentication persist across several devices and applications while maintaining security is not straight forward.
Mobile devices rely on the use of a single modality, such as fingerprint or iris, to perform biometric based user authentication. Such biometric systems suffer from a high false rejection and they require a user response such as swiping a finger.
A high false rejection rate could result from adjusting for low false acceptance rates. A false rejection is when a user who should be authenticated is denied. A false acceptance is when a user who should not be authenticated is accepted. Every biometric has a trade-off between false accepts and false rejects, achieving low equal error rates is difficult especially when errors due to failure-to-capture is taken into account. A high false reject rate corresponds to bad user experience.
The need for user to actively engage in the authentication process upon request leads to comparatively larger delays in user authentication and negatively impacts user experience. Users are less likely to adopt a biometric authentication solution if it requires substantially more effort.